The present invention relates to a medical energy irradiation apparatus whose inserting portion is inserted into a living body cavity or tract such as a blood vessel, digestive tract, urinary tract, abdominal cavity or thoracic cavity, and the bodily tissue is irradiated with the energy of a laser beam, microwave, radio wave or ultrasonic wave from an emitting portion provided on this inserting portion to treat tissues of a body in morbidity, and more particularly to a cleaning method for observation windows in a medical energy irradiation apparatus for pinpoint heat curing of only a tumor, such as cancer, prostatic hypertrophy or the like, in a deep part of the body.
There are known energy irradiation apparatuses for medical use whose long inserting portion is inserted into a living body by utilizing an existing body cavity or incising a small hole to emit a laser beam, microwave, radio wave or ultrasonic wave to irradiate and treat tissues of a body in morbidity by eliminating the tissues in lesion by degeneration, necrosis, coagulation, cauterization or vaporization.
This kind of medical energy irradiation apparatus, which in its operation to cure the ailment usually directly irradiates with energy a lesion located on or near the surface layer of tissues of a living body, is also used for heat curing of a lesion located deep inside tissues of a living body such as the prostate gland. There is also known a medical energy irradiation apparatus of which the vicinities of the energy emitting portion provided on the inserting portion is cooled with coolant. Where this medical energy irradiation apparatus is used, since the energy emitting portion or the surface layer and its vicinities of tissues of a living body in contact with the vicinities of that portion are cooled, they are protected from heat injury, and a deeper part of tissues of the living body is heated concentratively.
For instance, in International Application Published under PCT No. WO9304727, a technique of coagulating and contracting part of tumorous or prostatic tissues by irradiation with a laser beam is disclosed. By this technique, heating of the surface of the urethra in contact with a balloon is avoided by injecting a coolant into the balloon, and instead only the tumor or prostate gland within is heated. However, as the laser beam is emitted from a fixed laser emitting portion, the irradiating laser output has to be low in order not to heat the urethra surface, inevitably resulting in the inconvenience of having to continue irradiation for a long period of time.
In U.S. Pat. No. 5,292,320, there is disclosed an apparatus for curing prostatic hypertrophy by guiding laser beams through the urethra. In this apparatus, laser beams emitted at the same time from a plurality of irradiating units arranged in different positions are concentrated on a deep lesional region, i.e. the target point of irradiation, to generate a sufficient calorific value for heating and contracting the tissue in the lesional region.
Therefore, although the temperature around the target point of irradiation is higher than in the regions where laser beams do not overlap each other, as the paths of the laser beams are fixed, a high-temperature region is formed even in the vicinity of the surface layer of the urethra, where laser beams do not overlap each other. This phenomenon adversely affects the protection of the surface layer of the urethra. Thus the inability of this apparatus to cure only a deep lesional region while reducing injuries to the surface layer poses a problem. Furthermore, since the plurality of irradiating units are contained, it is difficult to thin a main body.
Further, E.P. 1075822 discloses a laser beam irradiation apparatus for curing prostatic hypertrophy by guiding a laser beam through the urethra.
As this irradiation apparatus has a configuration in which its laser beam emitting portion continuously shifts to concentrate the laser beam from the emitting portion on the target point, the surrounding tissues other than the target point are kept at low temperature while the target point is heated to high temperature. For this reason, this laser beam irradiation apparatus is able to minimize, even when the target point is located in the depth of tissues of a living body, injuries to tissues of the living body positioned between the emitting portion and the target point, thereby capable of ensuring greater safety for the patient.
Incidentally, in trying to cure prostatic hypertrophy using the laser beam irradiation apparatus described above, the doctor would determine the target point for the laser beam in the following procedure, for instance.
The doctor inserts the inserting portion of the laser beam irradiation apparatus into the patient's urethra, fixes the laser beam emitting portion to match the position of the patient's urethra surrounded by the prostate while observing the urethra by way of an endoscope inserted into the inserting portion through an observation window installed on the inserting portion, and irradiates the lesion with a laser beam while aligning the emitting portion with the intended irradiating direction of the laser beam.
Thus the doctor inserts to a prescribed extent the inserting portion in which the endoscope is inserted into the patient's urethra toward the urinary bladder, and searches for the target point according to the shapes of different parts of the urethra observed through the endoscope in that position. If the target point is not found in the field of vision observable through the endoscope in that position, the doctor will repeat the above-described procedure until the target point is found by further inserting the inserting portion deeper into the patient's urethra to another prescribed extent toward the urinary bladder or otherwise.
The doctor will also repeat the above-described procedure on each target point in the heat curing with this laser beam irradiation apparatus if there are a plurality of target points to be irradiated with a laser beam.
Now, the above-described positioning of the laser beam target point may give rise to the following problem. Thus, when inserting the inserting portion through the patient's urethra toward the urinary bladder, if the observation window provided in the inserting portion is smeared by bleeding from the patient, for example, the field of vision through the observation window may be narrowed.
However, with the conventional laser beam irradiation apparatus described above (E.P. 1075822), once the observation window provided in the inserting portion is smeared, there is no other way to restore the full field of vision through the smeared observation window than to extract the inserting portion out of the patient's body and remove the contaminant on account of the absence of any mechanism for cleaning the observation window as shown in FIG. 8 and FIG. 9.
Also, the laser beam emitting portion according to EP 1075822 is small as shown in FIG. 8 and FIG. 10, and has a complex structure to keep the laser beam irradiation stably in a prescribed direction (toward the target point) all the time while continuously shifting the irradiating position of the laser beam. For this reason, it is difficult to secure a sufficient space in which is to be arranged a detergent feed pipe for cleaning the smeared observation window, when it is smeared as described above, in the inserting portion.
This difficulty to secure a sufficient space in which is to be arranged a mechanism for directing the laser beam stably toward a prescribed site all the time while continuously shifting the irradiating position of the laser beam and a detergent feed pipe in the inserting portion in the apparatus according to E.P. 1075822 will be described more specifically with reference to FIG. 8 through FIG. 10.
Laser reflecting means 1113 is fixed by a pair of arms 1116 fixed to the right and left sides of a supporting member 1114 fixed to the tip of an optical fiber 1108, and the pair of arms 1116 are slidably fitted by a pair of first stubs 1117 formed on the right and left sides of the laser reflecting means 1113 into a pair of rail grooves 1152 provided in a wall member 1151 provided within a housing 1102 (see FIG. 8). The rail grooves 1152 here are in parallel to the lengthwise direction of a body 1101.
A pair of second stubs 1118 formed on the right and left sides of the laser reflecting means 1113 are slidably fitted into a pair of rail grooves 1153 provided in the wall member 1151 within the housing 1102. The rail grooves 1153 here are not in parallel to the lengthwise direction of the body 1101.
Thus, the laser reflecting means 1113 shown in FIG. 10, with its structure using the pair of arms 1116, the pair of first stubs 1117, the pair of parallel rail grooves 1152, the pair of second stubs 1118 and the pair of non-parallel rail grooves 1153, can stably direct laser beam irradiation at the target point all the time while continuously shifting the irradiating position of the laser beam.
However, there is the need to provide the aforementioned arms and grooves within the housing 1102, resulting in a complex structure not allowing low-cost production. Also as stated above, because of the limited available space, when the observation window is smeared, it is difficult to secure a sufficient space for arranging a detergent feed pipe for cleaning the smeared observation window within the inserting portion.